1. Field of the Invention
The present invention relates to retrofit interface units which are used to connect remote isolation devices to existing surge protectors.
2. Description of the Related Art
Remote isolation devices (RIDs) are commonly used to isolate a subscriber's circuitry from a telephone company's circuitry at a remote location. In the past, telephone companies have been required to service telephone lines and circuitry both inside and outside of a subscriber's home. Some time ago, however, changes in the law have resulted in telephone companies only being responsible for maintaining circuitry outside of the subscriber's house, and typically not being responsible for failed circuitry within the subscriber's house. Thus, the subscriber must hire an independent contractor or pay the phone company a service fee in order to have a professional service the telephone circuitry within the home. The RIDs allow the telephone company to determine whether or not a circuit fault exists in the wiring belonging to the telephone company or the wiring belonging to the subscriber. This affords considerable savings to the telephone company since the telephone company is not required to send out service personnel to inspect the wiring. The magnitude of these savings is further augmented due to the large volume of subscriber's (on the order of several millions) which telephone companies service. Therefore, RIDs have become very desirable due to the increased savings which these devices have rendered to telephone companies.
Because of the desirability of equipping a subscriber's home or business with RIDs, a number of schemes have been developed to retrofit these devices onto the terminals defining the boundary between the telephone company's circuitry and the subscriber's circuitry. Currently, telephone companies intend to retrofit each of the houses which does not already have an RID device connected at the telephone company/subscriber interface by going from home to home and installing retrofit RID devices. Because of the huge volume of customers involved in this retrofitting process, even small time or cost savings for each installation may add up to a considerable savings overall. Therefore, it is extremely important that the retrofitting of the RID devices be accomplished in as little timed and with as little cost as possible.
In most homes and businesses, the boundary between the subscriber and the telephone company lines is located at an over-voltage surge protector device which is normally located on a wall outside of a home, or in an electrical closet in a business. Thus, a number of retrofitting devices have been provided in the past to connect the RIDs to the terminals of a surge protector at the interface between the subscriber's wiring and the telephone company's wiring.
For example, one prior device, disclosed in U.S. Pat. No. 4,800,588, comprises a housing which is mounted onto the outside wall of a subscriber's home. The housing has a plurality of selectively accessible compartments which may contain circuitry such as an RID device. This and other such housings are typically very expensive and bulky. Further, these devices typically require a significant amount of installation time, and the drilling of holes into a homeowner's wall. In addition, due to their size, these retrofitting devices often take up large amounts of wall space so that it may not be feasible to mount such a device near a surge protector where wall space is limited. As a result, servicemen are often required to run extension lines from the surge protector to the mounting device, thereby increasing installation time, not to mention the aesthetically displeasing effects of such extensions.
In most businesses having multiple subscriber input lines, the surge protector devices consist of a series of separated terminals wherein all pairs of the subscriber terminals are located in one housing column and all pairs of the telephone company terminals are located in a second housing column. Each pair of subscriber terminals, with their corresponding pair of telephone company terminals, corresponds to a single, outside telephone line. A common example of such a multiple subscriber terminal is a conventional 66 block surge protector. Prior devices have also been developed for mounting RIDs onto such multiple subscriber terminals. For example, in one prior device a housing which encapsulates a RID includes a clip that fits over the subscriber column or the telephone company column. However, because each subscriber pair requires its own RID, this method of mounting RIDs proves very cumbersome. This is because the mounting apparatus extends over the face of the connecting block so that the RID not only covers the terminals to which it is connected, but also interferes with work being performed on adjacent terminals. Therefore, when it is required to service the multiple subscriber terminals, the RIDs which cover each terminal pair often become an obstruction which results in increased labor costs each time one of the multiple subscriber surge protectors is serviced. As the RID is largely for the telephone companies benefit, business consumers sometimes are unwilling to permit RIDs to be installed on block surge protectors because they increase labor costs for repairs which are the responsibility of the subscriber.
Therefore a need exists for a mounting apparatus which may be used to retrofit RIDs onto existing surge protectors, either in individual homes or businesses, without exhibiting the aforesaid disadvantages.